The present invention relates to a cleaning apparatus of the type comprising at least one suction device of a fluid, connected to a suction duct, and means for holding back any solid particles present in the sucked fluid.
Domestic cleaning apparatus providing for suction of an air-flow containing solid particles, also known by the name xe2x80x9cvacuum cleanerxe2x80x9d, usually comprises a suction pump connected to an external duct and means for separating and holding back the solid particles contained in the flow of sucked air. The suction pump creates an area of low air pressure in correspondence to the collecting section of the external duct, able to cause an air-flow containing any dust-or solid particles, directed toward the inside of the apparatus. Subsequently, the dust contained in the flow of sucked air is separated, for instance by means of a membrane filter, to allow clean air to be vented from the apparatus.
Therefore, in use, the operator directs the collecting section of the external duct, generally equipped with a shaped extremity, to above a specific surface of the object that needs cleaning and, operating, the pump, aspirates any solid particles present on the same surface into the cleaning apparatus. The airflow and sucked dust are induced to flow through a membrane filter, usually pouch-shaped, capable of holding back even very small solid particles. The membrane filter, however, placed between the collecting section and the suction pump, causes a notable loss of pressure in the suction circuit, and accordingly reduces the ability of the same apparatus to aspirate dust, because of the very small pore-dimension in the filtering membrane.
Furthermore, such membrane filter must be replaced regularly, because of the dust which accumulates during use and tends to offer increasing resistance to the flow of the air, involving the generation of a lower vacuum in correspondence to the collecting section of the suction duct and therefore degrading the performance of the cleaning apparatus. The operation of removal and substitution of the filter, which generally involves opening the body of the cleaning apparatus, separating the filter from the housing in which it is lodged, recovering the filter from the suction ducts and discharging it, assembling the new filter and closing the body, is not easy and requires the elimination, and consequent replacement of consumable materials.
Finally, whenever a liquid is erroneously sucked by the above described apparatus, the membrane filter (usually of paper material) could soften and tear because of the absorption of the same liquid. Such laceration would allow solid particles to flow into the suction circuit and to penetrate the suction pump, jeopardising the operation of the cleaning apparatus. Therefore, suction of liquids must be avoided by such apparatus.
On the other hand, cleaning apparatuses are known that, equipped with a steam generator and with means for the delivery of the steam, also comprise devices for the suction of liquids.
In such apparatuses, which allow the washing of the surfaces that are to be cleaned, a jet of steam under pressure is delivered that loosens any encrusted dirt and favours the mixing of the particles of dust with the water resulting from the condensation of the same steam. This mixture of water and dust is sucked simultaneously with the delivery of the steam by the cleaning apparatus and, for instance, made to fall by gravityxe2x80x94exploiting the weight of the mixturexe2x80x94into a collection container. In these embodiments, the sucked wet dust accumulates in the collection container and must be emptied regularly by the operator.
But, the cleaning apparatuses equipped with a steam generator and with means for the suction of liquids are not able to aspirate dry dust, or dust not mixed with water, because they don""t comprise means for separating the dust from the air-flow, such as for instance a membrane filter. In similar apparatuses, to avoid dust not mixed with water damaging the same suction device, the operation of suction is activated only simultaneously with the delivery of the steam.
One purpose of the present invention is to provide a cleaning apparatus that is able to aspirate both dry solid particles and liquids present on a surface and to separate the solid particles and the liquid from the flow of discharged air.
A further purpose of the present invention is to provide a cleaning apparatus that is particularly versatile and easy to use.
Another purpose of the present invention is to get a cleaning apparatus that allows only the suction of dust from dry surfaces or, alternatively, the delivery of steam and the subsequent suction of dust mixed with water.
These and other purposes are achieved by the cleaning apparatus according to the principal claim and the following dependent claims.
A cleaning apparatus according to the present invention comprises a suction device of a fluid toward the inside of the apparatus connected to an external suction duct, and means of holding back the solid particles, located between the suction device and the external duct. Such means for holding back the solid particles comprises a mixing chamber partially filled with a liquid and means for causing turbulence in the mixing chamber, in such a way as to create in the latter a saturated environment of liquid in suspension above the free surface of the same liquid.
In a preferred form of embodiment, the cleaning apparatus comprises further means for the reduction of the speed of the sucked fluid interposed between the means for causing the turbulence and the suction device.
According to a particular aspect of the invention, the means for causing turbulence and the means for the reduction of the speed of the sucked fluid comprise a first Venturi tube in fluid communication with the mixing chamber and with a further collection chamber. The Venturi tube is arranged above the free surface of the liquid contained in the mixing chamber.
In a further embodiment of the cleaning apparatus according to the present invention, the said mixing chamber and the collection chamber are in fluid communication with each other, either below or corresponding to the free surface of the liquid initially contained in the mixing chamber.
According to a preferential embodiment of the invention, the means for causing the turbulence comprises a further Venturi tube placed downstream of the first Venturi tube. Furthermore, membrane filtering means are present at least partially located in the first Venturi tube.
In another particular form of embodiment, the Venturi tube is of the divergent type and presents the reduced portion entry section in fluid communication with the mixing chamber, and the divergent portion exit section in fluid communication with the collection chamber.
According to another aspect of the invention, the collection chamber presents a discharging duct connected to the suction device and a sensor of the level of liquid present in the collection chamber; the sensor is connected to means for interrupting the operation of the suction device in the event of the level of the liquid in the mixing chamber reaching or exceeding a pre-set threshold. In a further form of embodiment, the cleaning apparatus according to the invention comprises a reservoir for the water, as well as means for generating and delivering steam and/or water at high temperature connected to this reservoir.
Some preferential embodiments of the cleaning apparatus according to the present invention will now be described by way of example and not of limitation, with reference to the attached drawings, in which: